Improved Defective Structure Low-Pass Filter

Abstract

The invention discloses an improved defective ground structure low-pass filter. The invention adopts a special two-step impedance structural unit, which adopts a structural mode of narrow rectangularconnection hexagonal structural unit, can shorten the length of the step impedance structural unit without reducing the load Q, has great degree of freedom in structure and design, and is easy to realize miniaturization of microwave device. In addition, the invention optimizes the defect ground structure of the bottom and changes the effective dielectric constant distribution of the substrate material, thereby affecting the current distribution of the ground plane and the transmission characteristics of the microstrip transmission line. Such a defective structure of the invention improves thelow-pass filtering characteristics of the low-pass filter by increasing the high impedance frequency width and the out-of-band rejection strength of the low-pass filter. Moreover, this kind of defectground structure, the structure is relatively simple, easy to electromagnetic field theory analysis and equivalent circuit modeling analysis, more suitable for the practical application of integratedcircuits advantages.

Description

technical field [0001] The invention belongs to the field of microwave technology, in particular to a low-pass filter with a defective structure. Background technique [0002] With the development of modern communication technology, the market has higher and higher requirements for the efficiency and anti-interference of communication equipment, which also leads to the research of high-performance microwave devices. The low-pass filter can suppress harmonic signals and interference signals, and provide a suitable working bandwidth for the communication system. The traditional low-pass filter has a large structure size, poor selectivity, and weak out-of-band suppression ability, so it is difficult to suppress interference signals and high-order harmonic signals. Through research in recent years, a series of new types of photonic bandgap structures (PBG, Photonic Bandgap), step impedance cascaded structures, adjustable filter structures, and electromagnetic bandgap structures...

AI Technical Summary

Problems solved by technology

The EBG structure needs to be loaded with a periodic structure, the modeling design and processing are more complicated, and it is not easy to miniaturize

Moreover, the band-stop characteristic parameters of the EBG structure are easily affected by various conditions, so the performance of microwave devices with the EBG structure is also unstable.

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